This is Unlucky the Inostrancevia pup. An albino in a desert climate, he was rescued from a short, painful life by a time and space traveler. She decided to keep him as a partner as she explored the "Shadow Worlds"--mysterious planets far from any sun that stay habitable through unknown means. Such cool, dark places are much more suitable for his sensitive eyes and skin.
Sometimes they enjoy a respite on a normal, sunlit planet, perhaps in a deep forest or a shaded canyon.